There's a French expression, "Cherchez la femme," which, literally translated, means "look for the woman." The expression originated in Alexander Dumas (pere)'s 1854 novel, The Mohicans of Paris. The idea is when a man acts criminally, he is probably doing so for reasons that involve a woman.
A better way to get to the bottom of most crimes would probably be, "Cherchez le sociopathe." Most crimes, at least most big crimes, have a sociopath behind them. There may be a woman in the sociopath's life, but she is near irrelevant compared to the driving force behind the crime -- the sociopath's absolute lack of compunction about committing it.
I read a book about Gypsies once which quoted an unnamed U.S. law enforcement officer as saying that there was no such thing as a Gypsy family which was not involved in crime of some sort. That's my general sense with sociopaths as well. Scratch a sociopath, find a criminal -- of some variety. Maybe their crimes are merely moral in nature, i.e., they take advantage of others while staying inside the letter of the law. But all sociopaths will always be destructive, however much they gussy up their bad behavior with self-righteous justifications and high flown language. And a high percentage break the law, whether or not they get caught.
This is an issue that FBI profilers pay attention to. A case in point was the Atlanta bomber. When Richard Jewell first discovered the pipe bomb in Atlanta's Centennial Park during the Atlanta Olympics in 1996, and helped evacuate the area, he was hailed as a hero. But FBI suspicion quickly turned to him after it turned out that he fit the profile of a potential bomber. (There have been numerous cases of sociopathic firemen who would set fires just so they could be first to the scene and be hailed for their heroism; and there have been cases of sociopathic nurses who would put their patients in mortal danger just so they could look good by coming in to "rescue" them. Sociopaths will do anything to look like a hero.) The fact that Jewell was first to the scene was in and of itself suspicious.
The President of Piedmont College, his former employer, reportedly said that Jewell was a "badge-wearing zealot" who would write up "epic police reports for minor infractions." (Dennis Rader, the BTK ("bind, torture, kill") serial killer of Kansas, was supervisor of the Compliance Department of Park City, and was called "overzealous and strict" by his neighbors, who would find themselves getting written up for the most minor infractions. Rader was also, by the way, President of the Congregation Council of the local Christ Lutheran Church as well as a Cub Scout leader.)
Jewell had been unable to keep a job in law enforcement, the field he wanted to work in, thus had settled for a job as a security guard. (There have been several serial killers, including Kenneth Bianchi (one of the two Hillside Stranglers), and Edmund Kemper, who were rejected for work as police officers.)
It seemed that Jewell fit the profile of a sociopathic criminal too perfectly for the FBI not to focus on him. Eventually, Eric Rudolph confessed to and was convicted of the bombing and Jewell was exonerated. But he probably was a sociopath. He just wasn't guilty of this bombing. The FBI profilers are an astute bunch: they know what personality traits to look for when looking for a killer.
The FBI regularly uses profilers to solve serial killings; they should probably do it with other kinds of crimes as well. First spot the sociopath, then look for the crime. Or if there is a crime with a number of suspects, if you see clues to a sociopathic character from other behaviors, you will generally have your man.
The ringleader of any gang is almost always the sociopath of the group. He is the most ruthless, the most fearless, the slyest, and the most manipulative. Sociopaths can even manipulate people who would be otherwise law-abiding into breaking the law. And he will not abide competition; if anyone else wants to be leader, the sociopath will do his best to destroy him.
It has always been one of the great injustices of law enforcement that the sociopath in a group -- the one who was most likely the ringleader, and possibly recruited the others to become involved in crime -- will also be the one who is quickest to rat on his buddies. The others, even though they may have been manipulated into crime by the sociopath in the first place, are more likely to be loyal to their buddies and not rat. The sociopath, who has no honor, will be the first to go for a deal. And since the prosecutors need someone to provide state's evidence, they will make a deal with the first to turn.
When the worst of the bunch gets off free, justice hasn't been served.
Sex criminals are required to register with the police when they move to a new neighborhood. This is partly because, as the experts in the field will tell you, they never really change. If only there were some way to force all sociopaths to register as well; they never change either.